`ValueGetter` is not supported in`map`

[veezhang]

ValueGetter is not supported inmap:

https://go.dev/play/p/cutaKAgIxHj

package main

import (
	"fmt"

	"github.com/expr-lang/expr"
	"github.com/expr-lang/expr/patcher/value"
	"github.com/expr-lang/expr/vm"
)

type customInt struct {
	Int int
}

func (v *customInt) AsInt() int {
	return v.Int
}

func (v *customInt) AsAny() any {
	return v.Int
}

func main() {
	env := map[string]any{
		"params": map[string]any{
			"ValueOne": &customInt{1},
			"ValueTwo": &customInt{2},
		},
	}

	program, err := expr.Compile(
		"params.ValueOne + params.ValueTwo",
		expr.Env(env), 
		value.ValueGetter,
	)
	if err != nil {
		fmt.Println(err)
		return
	}

	out, err := vm.Run(program, env)
	if err != nil {
		panic(err)
	}

	fmt.Println(out)
}

The code above produced the following error:

panic: invalid operation: main.customInt + main.customInt (1:17)
	 | params.ValueOne + params.ValueTwo
	 | ................^

goroutine 1 [running]:
main.main()
	/tmp/sandbox3933238168/prog.go:43 +0x249

Program exited.

In my scenario, it's not possible to define a specific struct. Is there any way to solve this problem?

[antonmedv]

Why do you need to use a value getter?

[veezhang]

Why do you need to use a value getter?

I have defined a generic type for params, I wang use params.{key} nor params.{key}.Value() in expr.

type(
	ParamValue struct {
		typ       ParamType
		boolVal   bool
		intVal    int
		floatVal  float64
		stringVal string
		arrayVal  []*ParamValue
		objectVal map[string]*ParamValue
	}
)

func (v *ParamValue) Value() any {
	switch v.typ {
	case ParamTypeBool:
		return v.boolVal
	case ParamTypeInt:
		return v.intVal
	case ParamTypeFloat:
		return v.floatVal
	case ParamTypeString:
		return v.stringVal
	case ParamTypeArray:
		return v.arrayVal
	case ParamTypeObject:
		return v.objectVal
	default:
		return nil
	}
}

func (v ParamValue) AsAny() any {
	return v.Value()
}

[veezhang]

This isn't the only example; ValueGetter is used in other places as well.
We found that it doesn't work in nested maps, but it works in top-level maps.